In the past, various embodiments have been proposed for a structure for fixing a rotational ring to a rotary shaft in this type of mechanical seal devices.
For example, known embodiments include an embodiment to fix with a set screw at the inside (e.g. Japanese Utility Model Publication H2-92170 (Patent Document 1)), an embodiment to fix with a sleeve at the outside (e.g. PCT International Publication WO2006/022378 (Patent Document 2)), an embodiment to fix with a seal nut (e.g. Japanese Utility Model Registration No. 2538900 (Patent Document 3)) or an embodiment to fix with two kinds of sleeves (e.g. Japanese Unexamined Patent Publication No. 2005-140258 (Patent Document 4)), etc.    [patent document 1] Japanese Utility Model Publication No. H2-92170    [patent document 2] PCT International Publication WO2006/022378    [patent document 3] Japanese Utility Model Registration No. 2538900    [patent document 4] Japanese Unexamined Patent Publication No 2005-140258